The P-47s reputation may have been a victim of its image. It’s not sleek and aerodynamic looking like the Spitfire or P-51 Mustang. It lacks the stylish gullwing of the F4U Corsair and has never gained the infamy of the Stuka. The plane is unusually….thicc? Seeing images of its crew standing next to their planes really demonstrates how huge the fuselage was. The crew of this P-47 clearly agreed. They painted the word chunky onto the engine cowl. But if you are like me, this should indicate to you that there was something unique about the plane, that the designers tried something different. The best way to illustrate this is through a size comparison. This is the P-51 Mustang. It’s a streamlined,athletic-looking plane...and this is the P-47. You could have literally fit a P-51 inside the P-47 with room to spare. It simply doesn’t look the part, but what if I told you its frame was purpose-built to fit one incredibly powerful supercharged engine. Just as its namesake, the A-10 ThunderboltII, was built around its gun, it’s ancestor was built around its colossal engine.
The massive Pratt and Whitney R-2800 Double Wasp.A two-row, 18 cylinders air-cooled radial engine with a massive displacement of 46 litres. The Merlin engine of the Spitfire and-51 Mustang for comparison, one of the most commonly used Allied engines of WW2, was 27litres. And this is just the powerplant, the P-47was also fitted with a supercharger that took up a significant volume of the aft fuselage, and this gave the P-47 some incredible high-altitude performance. This shows the basic layout of the engine and supercharger inside the P-47 fuselage. The P-47 had a massive air-intake just underneath the engine, big enough for a man to fit in. The air from this intake was not immediately funnelled into the engine, instead, it was routed to the back of the plane first. Where it split into two ducts. One flowed into a supercharger impeller, which compressed the air and returned it to the engine carburettor, while the secondary duct flowed into an intercooler to cool the air from the compressor section which had heated up as a result of the compression. Of course, this compressor section needed to be powered. This was done through hot energised exhaust which was collected from the engine through this collection ring in a separate duct system.
This air was funnelled to a lower turbine section of the supercharger before the hot exhaust was vented to the atmosphere here. At lower altitudes, less of this energised exhaust made it to the supercharger, as there are two gated exhaust nozzles on either side of the plane that gradually closed as the plane climbed in altitude. This ensured the R-2800 double wasp was supplied with plenty of cold compressed air even at27,000 feet, where other planes could not funnel enough of the oxygen needed to achieve full engine power. This wasn’t the only trick the P-47 had up it’s the sleeve.P-47D-4 variants and onward were fitted with a 30-gallon tank filled with an alcohol-water mixture located between the pilot and the engine in the firewall. In times of emergency, this mixture could be injected into the engine. This gave short bursts of additional horsepower, taking the engine from it’s already massive 2,000 horsepower to 2,300 horsepower. So how does spraying water into an engine increase horsepower? The water isn’t fuel and it displaces some air entering the engine surely. Your immediate thought would be that this reduces horsepower. To boot, water is corrosive and incompressible, which could cause some serious damage later injection increases horsepower in two ways. Both as a result of water’s cooling effects. When water is injected into the engine it absorbs heat from the air and engine in the process of evaporating. This increases engine pressure and lowers the temperature of the piston. Colder air is denser, and thus more air/fuel mixture is carried into the piston with each stroke, increasing the energy released in each power stroke.
The evaporation also cools hotspots in the engine that can cause pre-ignition of the air-fuel mixture. Meaning the air-fuel mixture ignites before the piston is at the bottom of its compression stroke and thus is working against the power strokes in the other cylinders, lowering the power output of the engine. The limited water supply meant this power boost was saved for emergency use only, but emergencies are the exact time a little boost in horsepower is needed. Whether that is climbing a little faster to regain an altitude advantage after a diving attack, taking off with a little extra weight, or simply speeding away from an aggressor. With all these design features, the P-47 was a fast plane with few planes being able to match its high altitude performance. Early versions of the P-47 did suffer from the poor climb and turning performance. That massive engine added a great deal of weight, and under the large fuselage needed to hold it, a great deal of parasitic drag too. To climb or turn, the engine and wings needed to provide the force necessary to lift the plane to a higher altitude or shift its direction. These characteristics did not affect the P-47sroll rate however, where it excelled thanks to fantastic aileron control. However, in a dog fight being outburned or out climbed was a death sentence. Climb rates were improved for the P-47D-22and onward with the addition of a new larger propeller, a 4-metre diameter propellor nicknamed the paddle prop. It had a longer chord and distinctive cuffs which helped channel more air into the engine. This new prop made the climb rate disadvantage marginal, surprising German pilots who have become accustomed to pulling up sharply to evade P-47s. [1]So the P-47 wasn’t the best out and out fighter. Surely that supercharger gave excellent high altitude performance, making it the perfect bomber escort. Yes and no, because of another design flaw it’s range was lacklustre. The huge fuselage and engine made the P-47a thirsty plane. It’s fuel tanks were always going to struggle to feed this hungry engine. The plane could carry 305 gallons in two tanks located around the cockpit.
The main L-shaped tank located in front of and below the pilot could hold 205 gallons, while the secondary tank located below and behind the pilot could carry an additional 100 gallons. These tanks gave the pilot between an hour and a half and 2 hours of flight time and only just 50 extra miles of range over the spitfire, a notoriously short-range fighter. The spitfire was primarily designed as an interceptor to protect British Airspace, the P -47 was not designed for this purpose and it's lack of range frustrated bomber crews who relied on its protection. The pilots of the Luftwaffe were perfectly aware of the p-47’s range issues and often waited for the pilots to turn for home before launching an attack. All but the earliest production runs of P-47scould carry a drop tank on a belly hardpoint, like this P-47D flying with a 75-gallon drop tank, which would have increased its range by 180 kilometres. However plumping, hardpoints, and wing reinforcement to allow forwarding mounted drop tanks were added insultingly late with the P-47D-15. This allowed the P-47 to carry 108-gallon drop tanks on each wing, increasing the operational range by380 kilometres. Allowing P-47s to reach as far as Frankfurt and Hamburg. These tanks, of course, affect the plane's performance, pushing weight outwards decreases the planes roll rate significantly, but they could be jettisoned if needed during a dog fight. This was not an ideal solution, and the P-51 Mustang was without a doubt a better escort and fighter plane. However, the P-47 shined elsewhere. Those hardpoints were not exclusively designed tocarry external fuel tanks, they were designed for weapons and the P-47 could carry an impressive payload. The P-51 Mustang had a max payload of 450kg across it’s two wing-mounted hardpoints and had 6 M2 machine guns with 1840 rounds. The P-47 in comparison could carry over twice the weight in bombs at 1,136 kilograms with4 M2 heavy machine guns in each wing. The guns were staggered like this to allow sideloading from each of their 350 round magazines. The P-47 was easily the heaviest hitting single-engine fighter of world war2, and it could take a hit too. The plane was affectionately nicknamed “TheJug”, short for Juggernaut, and for good reason. Durability is a difficult thing to quantify, and it’s hard to parse out survivor bias, but just like the A-10, photos of surviving planes tell a story. If you were crash landing any fighter in WW2, you would want it to be the P-47. There are countless photos of P-47 crash landings where the pilot lived to tell the tale.
All that ducting around the pilot provided cushioning from the impact, and the smooth belly of the aircraft, free from air scoops and other protrusions, minimized the risk of turnovers, which could crush and kill the pilot, or simply trap them inside the plane. The P-47 could take a lot of damage and keep flying. The liquid-cooled Merlin engines of the P-51 Mustang were not known for their ability to take a hit, but the air-cooled R-2800 double wasp radial engines were. The structure of the P-47 wings was incredibly durable and could stay intact with severe damage. The ducting for the supercharger provided some protection from bullets and did not cause catastrophic failure with a few bullet holes resulting in a drop in supercharger pressure, which at worst required the pilot to drop in altitude and lower power. The fuel tanks under the pilot were self-sealing and offered good protection from hits on the belly of the plane and the pilot had two armoured plates behind and in front of the cockpit. So, we have listed the P-47s disadvantages, how they were minimized and it’s advantages. What’s my rationale for saying it was one of the best planes of world war 2? People who learn their history from videogames will bash the P-47 for its slight disadvantage in dogfighting, which is true enough, but it disregards the brain of the pilot. The P-47 had its disadvantages ina dogfight, but it’s advantages are what the pilots were trained to use and they were trained well. Why engage in a dogfight when you have an altitude and speed advantage. The P-47 was the perfect hit and run fighter. Striking from above, often catching the enemy unaware, and using its speed advantage to escape. They were most certainly capable of dispatching 109s and FW 190s, as proven by countless light reports from pilots. ME 109s could most certainly out turn a single P-47, but out turning 2 or 3 was an insurmountable challenge, which was the challenge the Luftwaffe were met with as soon as the manufacturing prowess of the United States entered the EuropeanTheatre. The P-47 was like the M4 Sherman of the air, perhaps not the best vehicle on paper, but it got the job done and was there when you needed it. It was also the United States Air Force’sbest fighter bomber. This plane was the warthog of WW2. With the Luftwaffe threat all but vanquished by D-Day, the P-47 truly shined in Normandy. Becoming a feared bird of prey over Europe. The Allies quickly constructed advanced landing grounds in Normandy to create forward operating bases for their air forces, like St. PierreDu Mont located to the West of Omaha Beach. What was once a farmer’s field became fully-operational airfield just 12 days after d-day with access roads, fuel dumps, ammo depots and a 1500 metre long track surfaced in steel square mesh track. These advanced landing grounds gave even the shortest range fighter aircraft the ability to loiter in the air over Normandy and push deeper into German territory than before. At this stage of the war, the Luftwaffe threat was all but eliminated. In this battlefield, the P-47 was in its prime. St Pierre Du Mont was home to 344th fighter group flying P-47s and they helped rack up the P-47s astonishing destruction record. From D-Day to VE Day, 336 days in total, the P-47 is credited with destroying 86,000 railway cars, 9,000 locomotives, 6,000 armoured fighting vehicles and 68,000 trucks. This plane played a vital role in the success of the allied invasion, terrorising German troops attempting to supply the front line with divebombing attacks and strafing runs with its fearsome M2 heavy machine guns. Overall, the P-47 was a great all-round aircraft. As the M4 Sherman, it was not perfect and had its weaknesses, but its weaknesses were a direct consequence of its strengths.
The P-47 was a sturdy reliable plane that kept their pilots alive with plenty of firepower and tactical advantages to get the job done. A plane loved by pilots and the ancestor of the iconic A-10 Thunderbolt, who doubled down on the P-47s strengths, creating a plane dedicated to the close air support role. The role of close air support played a vital part in the Allied Invasion of Europe. The constant harassment German troops had to contend with while attempting to travel to Normandydelayed and blunted many of their counter-offensives.
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